I. Problem/Challenge.

Performing preoperative medical evaluation is a routine responsibility for hospitalists, either for patients under their own management or as part of consultation or comanagement. In contrast to outpatients, hospitalized patients receiving preoperative medical assessment generally require urgent or emergent surgery.

II. Identify the Goal Behavior.

The hospitalist performing preoperative evaluations must quickly evaluate the surgical patient's risk for medical complications, order and interpret necessary preoperative tests, and optimize the patient's medical condition. This requires both the ability to recognize when a patient has increased risk for complications (especially prohibitively high risk) as well as attention to efficiency and avoidance of unnecessary delays in surgery.

III. Describe a Step-by-Step approach/method to this problem.

The following sections describe an approach to the preoperative assessment of several organ systems. In general, there are three steps to performing this assessment.

Assess the patient's risk for medical complications based on clinical criteria.

Determine whether additional preoperative tests should be performed to clarify risk or assist with management.

Implement strategies to reduce the risk of complications.

Cardiac Risk Assessment

1. Clinical Risk Assessment: Estimating perioperative risk for major adverse cardiac events combines two elements: patient-specific risk and surgery-specific risk. Multiple validated risk assessment tools exist, including the Revised Cardiac Risk Index (RCRI), the Gupta Perioperative Cardiac Risk Index, and the web-based American College of Surgeon’s NSQIP surgical risk calculator. The RCRI (See Table I) is the most widely used and identifies six independent risk factors: high risk surgery (such as major vascular procedures and major operations performed on an emergent basis), ischemic heart disease, CHF, CVA/TIA, Diabetes requiring insulin, and preoperative creatinine >2. Whereas previous guidelines stratified patients to low, intermediate, or high risk for perioperative cardiac complications, the 2014 American College of Cardiology (ACC) / American Heart Association (AHA) Practice Guidelines replace this three tiered classification with two categories: “low” (<1%) or “elevated” (>1%) risk.

Table I.

Revised Cardiac Risk Index Predictors

Revised Cardiac Risk Index Predictors

High Risk Surgery (suprainguinal vascular operations or major abdominal or thoracic operations)

It is uncommon for cardiac risk to be considered excessively high for surgery (especially when urgent or emergent). In general, severe or unstable heart disease that requires urgent evaluation or management, regardless of the upcoming operation, should lead to delay or cancellation of elective surgery. Some examples include suspected acute coronary syndrome, decompensated CHF, critical aortic stenosis, and uncontrolled dysrhythmia.

2. Preoperative Testing: For urgent or emergent operations, preoperative testing, other than an ECG, should be usually omitted, as the results are unlikely to change management. In elective cases, patients at low risk of major adverse cardiac events should proceed to surgery without further cardiac testing. Patients in the elevated risk category should have their functional status assessed: if capacity is moderate or better, as defined by >4 METs, then further cardiac testing is not recommended. For patients with elevated risk in whom functional capacity is <4 METs or is unable to be determined, pre-operative exercise testing with cardiac imaging or pharmacological stress testing may be suitable if it will change perioperative management.

3. Risk Reduction Strategies: Prophylactic coronary revascularization did not lower perioperative cardiac complication rates in randomized trials, and is not recommended in the absence of indications independent of the planned surgery. Placement of coronary stents also puts patients at risk for catastrophic stent thrombosis if anti-platelet drugs must be stopped prematurely to avoid surgical hemorrhage. Elective surgery should be delayed for at least 30 days after placement of bare metal coronary stents and for 12 months after drug-eluting stents.

Beta-blockers have been demonstrated to reduce the risk of postoperative MI in higher risk patients. The 2014 ACC/AHA perioperative guidelines recommend beta-blocker therapy as follows:

Recommend continuing in patients who have been on beta-blockers chronically.

Reasonable to add beta-blockers in patients with intermediate or high risk myocardial ischemia on preoperative testing, or in patients with 3 or more RCRI risk factors.

Uncertain benefit to adding beta-blockers for perioperative risk reduction in patients with a compelling long-term indication but no other RCRI risk factors.

Beta-blockers should be started at a low dose (e.g., metoprolol 25 mg PO bid or atenolol 25 mg PO daily), long enough in advance to assess safety and tolerability, and slowly titrated to a dose that keeps the heart rate between 50-70 bpm and the systolic BP >100 mmHg. ACC guidelines recommend against initiating beta-blockers on the day of surgery. Aggressive dosing can increase perioperative mortality. Additional attention must also be paid when adding beta-blockers to other anti-hypertensive medications in the pre-operative period. Recent evidence from a large observational study suggests that in patients with hypertension, combination therapy with beta-blockers and other antihypertensive drugs was associated with an increased risk of major adverse cardiovascular events and mortality when compared to combination regimens that did not include a beta-blocker.

Statins may also improve outcomes in the perioperative period. ACC & AHA guidelines recommend that it is reasonable to add a statin in patients undergoing vascular surgery.

Pulmonary Risk Assessment

1. Clinical Risk Assessment: The most serious postoperative pulmonary complications are pneumonia, respiratory failure, and death from a pulmonary etiology. The strongest patient-specific risk predictor for pulmonary complications is advanced age. The presence of systemic disease, debility, and specific comorbid conditions such as COPD and CHF also increase risk. Major operations of the thorax and upper abdomen confer the highest surgery-specific risk. The American College of Physicians guideline (2006) describes multiple risk predictors, the most important of which are listed in Table II.

Chest radiography may be more useful in patients with known or suspect cardiopulmonary disease, especially if undergoing upper abdominal or thoracic surgery.

Pulmonary function testing or spirometry may be useful to diagnose suspected lung disease. There is no spirometric parameter cut-off that makes non-lung resection surgery prohibitively risky.

Serum albumin level <35 g/L predicts a higher risk of pulmonary complications. It is reasonable to measure albumin levels in patients suspected of having hypoalbuminemia.

3. Risk Reduction Strategies: The following strategies may reduce the risk of postoperative pulmonary complications.

Lung expansion maneuvers (e.g., incentive spirometry or deep breathing exercises) have been shown to prevent complications in some studies.

Smoking cessation may prevent pulmonary complications as well as wound complications. However, studies suggest that patients must quit smoking for 4-8 weeks before surgery to benefit.

Patients with chronic lung disease should have their pulmonary function optimized prior to elective surgery.

While it is reasonable to optimize nutritional status before non-urgent surgery, do not initiate enteral or parenteral nutrition solely to reduce pulmonary risk.

Perioperative Endocrine Issues

Diabetes Mellitus: Diabetic patients are increased risk for surgical site infections, and that risk correlates with the severity of diabetes. For elective operations, it is appropriate to assess the patient's degree of glycemic control using hemoglobin A1c level or glucometer diary entries. Patients with very poor preoperative glucose control should postpone elective surgery until a more appropriate treatment regimen has been implemented. The inpatient management of diabetes (Glycemic Control of Hospitalized Patient) is described separately. Certain issues are particularly relevant for surgical patients:

Hyperglycemia (due to high levels of counter-regulatory hormones) and hypoglycemia (due to NPO status or anorexia) are both frequently seen in surgical patients.

Tight glycemic control may be beneficial in cardiac surgery patients in critical care units, but in other populations, it was associated with worse outcomes. In general, glycemic control targets for surgical patients should be the same as for nonsurgical patients.

Type 1 diabetics require insulin regardless of their glycemic control. They should be managed with an insulin infusion when not eating in the perioperative period.

Glucocorticoid therapy (commonly used in neurosurgical patients) can cause severe post-prandial hyperglycemia with relatively little effect on fasting glucose. Higher doses of meal-time insulin, rather than basal insulin, may be needed.

Adrenal Insufficiency: Patients with dysfunction of the hypothalamic-pituitary-adrenal axis (either due to intrinsic disease or suppression from exogenous glucocorticoid therapy) may be at risk for perioperative cardiovascular collapse. A common but unproven practice is to provide supplemental "stress-dose" steroids to patients with known or suspected adrenal insufficiency.

Patients taking the equivalent of 20 mg of prednisone daily for 3 or more weeks may be at risk for adrenal insufficiency.

Patients taking steroids for less than 3 weeks or at a daily dose of prednisone of 5 mg or less are unlikely to be at risk for perioperative adrenal insufficiency.

Patients should continue their usual maintenance dose of steroids perioperatively.

If supplemental glucocorticoids are given, a reasonable regimen is to give hydrocortisone 50 mg IV immediately prior to surgery, followed by hydrocortisone 25 mg IV every 8 hours for 24 hours.

Thyroid Disease: Patients with uncontrolled thyrotoxicosis can develop thyroid storm after surgery. An endocrinologist should be consulted if such patients require urgent or emergent surgery. Similarly, patients with severe, symptomatic hypothyroidism should delay elective surgery until adequate thyroid hormone replacement can be achieved. Mild or asymptomatic hypothyroidism is generally well tolerated during surgery.

Pheochromocytoma: This rare condition is described in a separate module. Patients with suspected pheochromocytoma should have this condition ruled out before undergoing all but emergency surgery. An endocrinologist should be consulted when a patient with known or suspected pheochromocytoma undergoes surgery.

Hematologic Issues

Anemia: The evaluation and management of anemia is described in detail in separate chapters. Anemia is commonly discovered preoperatively and develops routinely after surgery.

Previously unrecognized anemia should be evaluated prior to elective surgery. For urgent surgery, undertake a limited assessment to rule out acute, potentially life-threatening processes such as hemorrhage or hemolysis.

Severity of preoperative anemia correlates with postoperative mortality rates. However, it is not known whether correction of anemia prior to surgery improves outcomes. There is no specific preoperative hemoglobin level that should prompt transfusion. The decision to transfuse prior to surgery must also consider comorbidity (especially cardiopulmonary disease), the type of surgery, and the anticipated blood loss.

Postoperative transfusion decisions must also be individualized. A limited number of studies failed to show that an aggressive transfusion strategy (e.g., keeping the hemoglobin > 10 mg/dL) leads to better outcomes than a more restrictive transfusion strategy.

Assessment of Bleeding Risk: The evaluation of specific disorders of hemostasis is described in detail in separate chapters. A directed bleeding history should be performed prior to surgery.

Historical features suggesting an increased risk of bleeding include: unprovoked ecchymoses >5 cm on the trunk, menorrhagia with iron deficiency, frequent unprovoked epistaxis or gingival bleeding, hemarthrosis, prior excessive bleeding after surgery, personal or family history of bleeding diathesis, severe renal or liver disease, and use of medications that impair hemostasis.

Laboratory testing (PT, aPTT, and platelet count) is not routinely needed, but should be considered if history is unreliable or suggests increased bleeding risk.

Management of Chronic Anticoagulation: While patients on chronic anticoagulation with warfarin must usually interrupt therapy prior to major surgery, those undergoing surgeries with low bleeding risk - such as minor skin surgery, cataract surgery, or minor dental surgery - may be able to continue warfarin in discussion with the surgical team. In cases where anticoagulation must be held, determination of thromboembolic risk helps to identify patients in which “bridging” with low molecular weight or unfractionated heparin may be indicated. The following recommendations are based on the 2012 American College of Chest Physician guidelines; some recommendations are not supported by strong evidence.

Recently, the BRIDGE Trial evaluated the utility of pre-operative “bridging” anticoagulation with low-molecular weight heparin (LMWH) in patients with atrial fibrillation and risk factors for stroke who were undergoing surgery. There was no significant difference in the incidence of arterial thromboembolism in patients who were bridged and those who were not bridged. However, the incidence of major bleeding was significantly higher in patients bridged with LMWH.

Management must be individualized to balance bleeding and thromboembolic risk, as well as consideration of patient and surgeon preferences. See Table III.

Perioperative management of anticoagulation with warfarin

Evidence for perioperative management of oral direct thrombin and Xa inhibitors is lacking; an approach based largely on consensus and expert opinion is presented in Table IV. The rapid onset and offset of these agents generally makes bridging anticoagulation unnecessary.

A risk prediction calculator based on MELD score that estimates both short-term and long-term postoperative mortality is available at http://www.mayoclinic.org/meld/mayomodel9.html

Preoperative Testing: Routine screening of liver enzyme levels is not recommended, but should be pursued in patients with suspected hepatitis. Calculation of CTP classification and MELD score requires measurement of serum albumin, total bilirubin, INR, and creatinine and should be done in patients with known or suspected cirrhosis. Further diagnostic testing and imaging studies depend on the specific clinical findings and the timing of surgery, and are described in other chapters.

Risk Reduction Strategies: In general, the management of cirrhosis in surgical patients is similar to its management in nonsurgical patients.

Coagulopathy: Vitamin K may improve coagulopathy if nutritional deficiency is a contributing factor. Patients with severe coagulopathy may require fresh frozen plasma transfusion, usually aiming for INR of 1.5 or less. Patients with thrombocytopenia may require platelet transfusion, but response to transfusion may be limited in cirrhotic patients due to splenic sequestration.

Ascites: Significant ascites can impair abdominal wound healing and impede respiratory mechanics. Elective surgery should be delayed until ascites can be controlled medically with diuretics. If surgery is urgent, consideration should be given to therapeutic paracentesis.

Encephalopathy: Hepatic encephalopathy often worsens after surgery due to fluid/electrolyte imbalance and use of psychoactive analgesics and sedatives. Elective surgery should be delayed until encephalopathy is controlled with lactulose or antibiotics. It is not necessary to start these medications prophylactically in patients who don't usually require them. Postoperatively, attention must be given to fluid and electrolyte balance, and the doses of analgesics and sedatives should be minimized.

IV. Common Pitfalls.

In performing preoperative medical assessments, be sure to avoid:

"Clearing" the patient for surgery: The hospitalist should not assume sole responsibility for determining whether it is safe to proceed to surgery or state that the risk is low enough to operate. The aim of the preoperative assessment is to inform the surgeon and anesthesiologist about the patient's risk for complications, in order to better weigh risks and benefits.

Overstepping your qualifications: The generalist should not advise the anesthesiologist about anesthetic technique or intraoperative monitoring. Nor should the generalist advise the surgeon about surgical technique.

Ordering unnecessary tests: For urgent or emergent surgery, prognostic testing will rarely influence medical decision-making and can needlessly delay surgery. Before ordering any preoperative tests, consider the likelihood of an abnormal result and determine how the results will change management.

Failing to follow up: If the preoperative assessment identifies that the patient has substantial risk for medical complications, the hospitalist should follow up after the operation.

V. National Standards, Core Indicators and Quality Measures.

Severity quality assessment and improvement programs have been developed for surgical patients. Many of the core measurements in these programs deal with techniques to prevent infections that resulted directly from surgery, which is usually the responsibility of the surgeon and anesthesiologist, rather than the generalist/hospitalist (with the exception of endocarditis prophylaxis). Other core measures may be influenced by the actions of the consulting or comanaging hospitalist.